Filename: 201-bridge-v3-reqs-stats.txt
Title: Make bridges report statistics on daily v3 network status requests
Author: Karsten Loesing
Created: 10-May-2012
Status: Reserve
Target: 0.2.4.x

Overview:

  Our current approach [0] to estimate daily bridge users is based on
  unique IP addresses reported by bridges, and it is very likely broken.
  A bridge user can connect to two or more bridges, so that unique IP address
  sets overlap to an unknown extent.  We should instead count requests for
  v3 network statuses, sum them up for all bridges, and divide by the
  average number of requests that a bridge client makes per day.  This
  approach is similar to how we estimate directly connecting users.  This
  proposal describes how bridges would report v3 network status requests
  in their extra-info descriptors.

Specification:

  Bridges include a new keyword line in their extra-info descriptors that
  contains the number of v3 network status requests by country they saw
  over a period of 24 hours.  The reported numbers refer to the period
  stated in the "bridge-stats-end" line.  The new keyword line would go
  after the "bridge-ips" line in dir-spec.txt:

  "bridge-v3-reqs" CC=N,CC=N,... NL
      [At most once.]

      List of mappings from two-letter country codes to the number of
      requests for v3 network statuses from that country as seen by the
      bridge, rounded up to the nearest multiple of 8. Only those requests
      are counted that the directory can answer with a 200 OK status code.


[0] https://metrics.torproject.org/papers/countingusers-2010-11-30.pdf

